Electrocardiographic Findings in Patients with Acute Methadone Poisoning

Background: Methadone as a synthetic opioid is widely used for treatment of opioid dependency. One of the causes of methadone related sudden death is cardiac toxicity. This study was aimed to determine the electrocardiographic changes in acute methadone poisoning. Methods: This is a cross sectional study on patients older than 12 years old with acute methadone poisoning who were admitted in Loghman poisoning center at 2010-2011. Data analysis was done by means of SPSS version 16 and appropriate statistical tests at the significant level of P < 0.05. Results: In one year period, 51 patients with mean age of 40.59±18.27 (31-51) years, including 39 males, with acute methadone poisoning were included in to the study. Seven patients (13.7%) were acutely poisoned, 29 patients (56.8%) had acute on chronic methadone poisoning and others had not reliable history. The mean time of PR, QRS and QTc were 150.2±34.22, 77.06±13.89 and 421.76±43.04ms, respectively. The prolongation of PR, QRS and QTc were observed in 9.8%, 1.96% and 17.6% of patients, respectively. A significant statistical association was observed between PR prolongation and type of poisoning and QRS prolongation and outcome (P=0.035 and 0.009). Conclusion: The findings of this study indicate the occurrence of cardiac toxicity in patients with acute methadone poisoning. Further studies are required on acute methadone poisoning in patients with known previous cardiac status.